Discussion:
Yale fluid coupling

Working on an old dog kgp51at-60uf lift truck. Thanks to this site I have decoded the model number. The poor fellow has been ignored, patched, cobbled and generally not cared for for decades. Good news is the Chrystler engine runs very smooth with no smoke, the hydraulics all work and the previous owner mentioned that the lift cylinder leaks bad at the top of stroke. It had no brakes, little of the wiring was left, bad fuel pump, clutch not working and paper wasps everywhere. I have repaired most everything and am working on the clutch.

I have torn into it and have the top of the 2 speed transmission off, the manual clutch removed and will have the fluid coupling out this afternoon.

My questions revolve around the fluid coupling. Original symptoms were that even after adjusting the throw-out bearing the clutch would not release and I could not put the transmission in gear. If I held the clutch peddle in and started the engine with the transmission in gear, I got some odd noises, rattling, scraping and the truck would try to move. I never tried the accelerator, not knowing how the system was supposed to work. Looking in the top opening of the bell housing, I knoticed a large amount of play between the clutch housing and the flywheel. Thinking "that's not how a clutch should be. It's supposed to be bolted to the flywheel"....not knowing about the fluid coupling at the time. I understand now but something is worn somewhere. It shouldn't wobble that much. The clutch disk is pressed against an intermedia flywheel that is connected to the output of the fluid coupling.

The pilot bearing is worn but not gone. The splines between the pilot shaft and the clutch disk wobble a bit. The carrier bearing going into the transmission is solid and seems fine. Most of the play seems to be in the output shaft of the fluid coupler. Its as if the entier clutch, intermediat flywheel and pressure plate are all suspended by the output shaft of the fluid coupling.

So far it looks like the fluid coupling may be worn out. It has some fluid in it and so far I don't see any signs of leakage. As much as that output shaft wobbles, it should be leaking!

If anyone has experience with this fluid coupling, your thoughts would be appreciated. Even an exploded view of the thing would help.

Details to follow! Thanks all.
  • Posted 20 Aug 2023 05:30
  • By keshka_k
  • joined 17 Jun'19 - 8 messages
  • Oregon, United States
Showing items 1 - 3 of 3 results.
Too old I quess. No response to this post after four days. I was hoping for some help.
  • Posted 25 Aug 2023 01:06
  • By keshka_k
  • joined 17 Jun'19 - 8 messages
  • Oregon, United States
marked up photo: https://photos.app.goo.gl/3EGRAm2iQqYSAGp57
  • Posted 20 Aug 2023 12:27
  • By keshka_k
  • joined 17 Jun'19 - 8 messages
  • Oregon, United States
Note: serial number is J-012516

After today, my main question is how to get the coupler off. No bolts show through the starter port. The lower bell housing is part of the transmission and has no openings. I found a snap ring in the output port, removing it let a spring pop out and let the output hub droop more. I am working on a special tool to remove a notched ring about 3" in diameter but I don't think that is what holds the FC to the flywheel. I hope I don't have to remove the engine to get the FC off. That would suck.
  • Posted 20 Aug 2023 12:05
  • By keshka_k
  • joined 17 Jun'19 - 8 messages
  • Oregon, United States

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